Premature end of response header

I was experimenting with turning gzip off and on to see if it made a performance difference as we have been experiencing very high loads.
Turning it off didn't seem to make any difference but we used a lot more bandwidth.
I turned it back on and you can view the boards but you can't login or post
The litespeed log is showing:
2006-06-10 13:07:03.933 [NOTICE] [65.35.238.174:1092-0#disboards] Premature end of response header.
2006-06-10 13:07:04.717 [NOTICE] [72.30.101.142:35751-0#disboards] Premature end of response header.
2006-06-10 13:07:07.616 [NOTICE] [72.30.111.29:49311-0#disboards] Premature end of response header.
2006-06-10 13:07:07.982 [NOTICE] [72.30.110.159:58989-0#disboards] Premature end of response header.
2006-06-10 13:07:08.867 [NOTICE] [72.30.132.226:59901-0#disboards] Premature end of response header.
2006-06-10 13:07:10.039 [NOTICE] [72.65.185.16:50705-0#disboards] Premature end of response header.
2006-06-10 13:07:20.259 [NOTICE] [72.30.103.155:34902-0#disboards] Premature end of response header.
2006-06-10 13:07:23.110 [NOTICE] [72.30.103.19:52149-0#disboards] Premature end of response header.
2006-06-10 13:07:23.641 [NOTICE] [72.30.132.155:47149-0#disboards] Premature end of response header.
2006-06-10 13:07:25.974 [NOTICE] [68.64.254.43:2983-0#disboards]

When I look at the source of a page that is having an error it says:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=windows-1252"></HEAD>
<BODY></BODY></HTML>

The most important question is 1. Since something changed that caused this problem to happen. Finding out what changed will reveal the source of the problem. Increase in traffic should not cause this problem. Test your php binary by going "/lswsinstall/fcgi-bin/lsphp -i" to see if you get any errors from the command or in the "/lswsinstall/logs" log files.

Interesting- that made a small bit of progress, now we can log in etc but still get a blank page when trying to reply to a thread
The really strange thing is that in these blank pages view source is empty and the log is no longer showing "premature end of response header" errors
any thoughts?

This appears to be fixed now. The new php fixed the log in problem and the blank page problem was caused by vbulletin settings. Even though I chaged them directly through a mysql query they didn't really change untill I went into the admin panel and clicked apply
strange